1. Improved limits for violations of local position invariance from atomic clock comparisons
- Author
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Lange, R., Huntemann, N., Rahm, J. M., Sanner, C., Shao, H., Lipphardt, B., Tamm, Chr., Weyers, S., Peik, E., Lange, R., Huntemann, N., Rahm, J. M., Sanner, C., Shao, H., Lipphardt, B., Tamm, Chr., Weyers, S., and Peik, E.
- Abstract
We compare two optical clocks based on the $^2$S$_{1/2}(F=0)\to {}^2$D$_{3/2}(F=2)$ electric quadrupole (E2) and the $^2$S$_{1/2}(F=0)\to {}^2$F$_{7/2}(F=3)$ electric octupole (E3) transition of $^{171}$Yb$^{+}$ and measure the frequency ratio $\nu_{\mathrm{E3}}/\nu_{\mathrm{E2}}=0.932\,829\,404\,530\,965\,376(32)$. We determine the transition frequency $\nu_{E3}=642\,121\,496\,772\,645.10(8)$ Hz using two caesium fountain clocks. Repeated measurements of both quantities over several years are analyzed for potential violations of local position invariance. We improve by factors of about 20 and 2 the limits for fractional temporal variations of the fine structure constant $\alpha$ to $1.0(1.1)\times10^{-18}/\mathrm{yr}$ and of the proton-to-electron mass ratio $\mu$ to $-8(36)\times10^{-18}/\mathrm{yr}$. Using the annual variation of the Sun's gravitational potential at Earth $\Phi$, we improve limits for a potential coupling of both constants to gravity, $(c^2/\alpha) (d\alpha/d\Phi)=14(11)\times 10^{-9}$ and $(c^2/\mu) (d\mu/d\Phi)=7(45)\times 10^{-8}$., Comment: 6 pages, 3 figures
- Published
- 2020
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